"Sufi orders and the State in West Africa and the USA," paper for the atelier on Globalization and Islamic Identities in Africa, ISIM, Leiden, 18-20 April 2001.

"The Polemics concerning Sufism and the Sufi Orders in Post- colonial West Africa", paper presented at the International Symposium "Sufism and its opponents" Utrecht, May 1995.

"Ibrahim Niasse et l'�mergence de la Jama'at al-fayda en Afrique de l'Ouest," paper delivered at the International Conference on Muslim Societies in West Africa under French Colonial Rule, Aix-En-Provence, France, September 1994.

"West African Muslim Missionary Movements and Security," paper delivered at the workshop on Transnational Religious Regimes organised by the Committee for International Peace and Security of the Social Science Research Council, New York October 1993 (revised and expanded version of a paper delivered in April 1992 in Chicago).

"Sufi Transnationalism and da'wa: some thoughts on West African Networks" paper deliverd at the workshop on Transnational da'wa organised by the Joint Committee for the Comparative Study of Muslim Societies of the Social Science Research Council and the American Council of Learned Societies. Wales, 11-12 October 1992.

"Some Considerations on Sufi Transnationalism with Particular Reference to the Niassene Tijaniyya," paper deliverd at the workshop on Transnational Religious Regimes organised by Committee for International Peace and Security of the Social Science Research Council, Chicago, 24-26 avril 1992.

"L'Islam r�formiste comme base d'affirmation identitaire : le cas du mouvement Izala � Kano," paper for the conference Islamic Identities in Africa convened by the School of Oriental and African Studies of the University of London and the Center for the Study of World Religions of Harvard University, London, 18-20 April 1991.